Process for the treatment of iron and steel to form a permanent black finish thereon.



W. R. SWAN. PROCESS FOR THE TREATMENT OF IRON AND STEEL TO FORM A PERMANENT BLACK FINISH THBREON.

APPLICATION FILED JULY so, 1913.

Patented Nov. 25, 1913.

vwemtoz UNITED STATES PATENT OFFICE.

WILLIAM R. SWAN, OF BRIDGEPORT, CONNECTICUT.

PROCESS FOR THE TREATMENT OF IRON AND STEEL TO FORM A PERMANENT BLACK FINISH THEREON.

Specification of Letters Patent.

Patented Nov. 25, 1913.

Application filed July 30, 1913. Serial No. 782,078.

To all whom, it may concern:

Be it known that I, WILLIAM R. SWAN, citizen of the United States, residing at Bridgeport, in the county of Fairfield and State of Connecticut, have invented certain new and useful Improvements in Processes for the Treatment of Iron and Steel to Form a Permanent Black Finish Thereon, of which the following is a specification.

Thepresent invention relates to a new and novel process for the treatment of such metals as iron and steel to form a permanent black finish thereon, the said black finish being rust resisting under various atmospheric conditions and the ordinary conditions of use.

The object of the invention is to provide a process of this character which produces a durable and inexpensive finish upon the metal, which does not require numerous and repeated treatments of the metal, and which only requires a few minutes of time, whereas those processes now in common use require from two to eight hours.

With this and other objects in view, the process consists in treating the metal by successive steps in a novel manner as will be hereinafter described.

Oneform of apparatus for carrying out the process is illustrated by the accompanying drawin in which the figure is a vertical sectional view through a muflle furnace and a super-heater.

The iron or steel articles upon which it is desired to produce the permanent black finish are first laced in a suitable chamber such as a mu 0 furnace, to ether with a quantity of co per sulfate, sa -ammoniac or aluminum ch orid, tannin, and glucose. These chemicals may be placed in the furnace in any manner, as a mixture in a single tray, and any suitable proportion of the chemicals may be employed, although I have found by-experiment that the chemicals can be advantageously used in an'ordinary muf-. fle furnace in the following proportions. Copper sulfate 2. part, Sa -ammoniac Tannin Glucose The iron or steel articles together with the chemicals which have been placed in the mufile furnace are heated to about 1050 Fahr. and superheated steam injected into the furnace for a period of about thirty minutes. The steam for this purpose may be drawn from an ordinary water steam boiler at about five pounds pressure and superheated in any conventional manner. After the iron and steel articles have thus been heated in the mufile furnace and subjected to the action of superheated steam in the presence of the chemicals they are withdrawn from the furnace and permitted to cool, after which they are submerged in paraflin oil which has been heated to a temperature of about 150 Fahr. The articles which have thus been treated are permitted to dry by exposure to the air, and a dead black rust resisting coating is thereby rovided. The pores of the metal wil be opened up as it expands under the action of the heat, and this dead black rust resisting coating will penetrate into the metal as far as this opening up of the pores will permit.

The copper sulfate is a metallic salt and apparently forms the base. on the metal which resists the rust, the other chemicals producing the finish which with the warmed paraffin oil gives the dead black desired. Should a heavier coatin be desired, this can be obtained by a repetition of the process, although this is ordinarily not necessary.

- It is not absolutely necessary to use tannin as an ingredient of the compound, and the tannin may be entirely omitted, if desired, although it has been found that a somewhat better finish is obtained where this ingredient is used. I

In the drawing, which illustrates a sectional view through a muflle furnace and super-heater adapted for use in carrying out the rocess, the numeral 1 desi ates the mu e furnace which may be of t e conventional construction and is rovided with the usual door 2 through whic the iron or steel articles 3 to be treated are placed in the furnace" and removed therefrom. Vents 4 are provided in the walls of the furnace 1, the said vents being shown in the resent instance as located in the top of t e furnace. A shelf 5 is provided at-the back of the furnace for supporting a tray 6 in which the chemicals are placed. A suitable opening 7 is provided through which the tray 6 may be placed upon the shelf or removed therefrom from the back of the furnace, a suitable door 8 being provided for normally closing the opening 7. Super-heated steam is injected into the furnace through a pipe 9 which leads from a coil 10 in a superheater 11, the said coil receiving steam from an ordinary water steam boiler (not shown). An oil burner 12 or the like of any conventional construction may be utilized in connection with the superheater for heating the steam. The articles 3 to be treated are placed in the furnace through the door 2 in the usual manner and acted upon as has previously been described.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent, is

1. The process for the treatment ofiron and steel to form a dead black rust resisting finish which includes the following steps, heating the iron being treated, subjecting it to the action of superheated steam in the presence of a metallic salt adapted to form a base thereon while still heated,

cooling and submerging the iron in heatedparaffin oil.

2. The process of treating iron or steel to produce a dead black rust resisting finish thereon, which includes the following steps, heating the iron being treated, subjecting it to the action of superheated steam in the presence of a metallic salt adapted to form a base thereon and other chemicals adapted to cooperate therewith to produce a finish, cooling the iron and submerging it in heated paraflin oil.

, 3. The process of treating iron and steel to produce a dead black rust resisting finish thereon, which includes the following steps, heating the iron being treated, subjecting it to the action of superheated steam in the presence of copper sulfate while thus heated, cooling the article and submerging it in heated paraffin oil.

4. The process of treating iron and steel to produce a dead black rust resisting finish thereon, which includes the following steps, heating the iron being treated, subjecting it to the action of superheated steam in the presence of copper sulfate and salammoniac while thus heated, cooling the arlticle and submerging it in heated paraffin o1 5. The process of treating iron and steel to produce a dead black rust resisting finish thereon, which includes the following steps,

heating the iron being treated, subjecting it to the action of superheated steam in the presence of copper sulfate, sal-ammoniac, and glucose while thus heated, cooling the iron and submerging it in heated paraflin oil.

6. The process of treating iron and steel to produce a dead black rust resisting finish thereon, which includes the vfollowing steps, heating the iron being treated, subjecting it to the action of superheated steam in the presence of copper sulfate, sal-a'mmoniac, and glucose, cooling the iron and submerging it in heated parafiin oil, and finally drying and cooling the iron by exposure to the am 7. The process of treating iron and steel to produce a dead black rust resisting finish thereon, which consists in heating the iron to about 1050 Fahr., subjecting it to the action of superheated steam in the presence of copper sulfate, sal-ammoniac and glucose while thus heated, coolin the article and submerging it in para n o-il heated to about 150 Fahr., and finally cooling and drying the iron by exposure to the air.

8. The process of treating iron and steel to produce a dead black rust resisting finish thereon, which includes the following steps, heating the iron being treated, subjecting it to the action of superheated steam in the presence of copper sulfate, sal-amrnoniac, tannin, and glucose, cooling the iron and submerging it in heated paraffin oil, and

WILLIAM R. SWAN.

Witnessesi F. E. MORGAN, F. P. MUNICH. 

